Between the eighth century and the thirteenth, scholars from Cordoba to Bukhara translated, argued, measured and built. Some of what they made is still in daily use: the word algebra, the names of the bright stars, stitches the body absorbs. Some of it is still underground, like the four-fifths of the capital at Samarra that nobody has excavated.
Every tile in a Islamic Golden Age game carries one of these. Open one to read it now, or leave them for the board to hand you.
Scholars and Translators
nine stories
1The book title that became a word for math
On the tile: Al-Khwarizmic. 820
Around 820 a scholar working in Baghdad wrote a manual for handling equations and called it Hisab al-jabr wa'l-muqabala. Al-jabr meant completion, the business of clearing negative terms out of an equation. Al-muqabala meant balancing, reducing matching terms on both sides. Europe borrowed the first word and got algebra. It borrowed his name too: a Latin version of his book on Indian reckoning, Algoritmi de numero Indorum, put the word algorithm into the language.
Hunayn ibn Ishaq was a Nestorian Christian from southern Iraq who spent his working life in Baghdad, at the center of the ninth-century effort to put Greek learning into Arabic. Ten years before he died he added up his versions of Galen alone: ninety-five in Syriac and thirty-four in Arabic. He wrote his own books as well. One of them reached Europe in Latin as the Isagoge, where it set the basic framework of medieval and early modern medicine.
Thabit ibn Qurra was a native of Harran and a member of the Sabian sect, not the Muslim majority around him. His first language was Syriac, based on the East Aramaic dialect of Edessa, and he was fluent in Greek and Arabic besides. That combination made him valuable: he translated and revised many of the important Greek works. He also left a rule that generates amicable numbers, pairs in which each number is the sum of the other's proper divisors.
Al-Kindi is described as the first self-identified philosopher in the Arabic tradition, and he spent his career making Greek thought usable in Arabic. Contemporaries objected that foreign ideas had no place in Muslim learning. In the first section of his On First Philosophy he answered them: "We must not be ashamed to admire the truth or to acquire it, from wherever it comes." Truth, he went on, is not demeaned by whoever happens to be carrying it.
Al-Biruni corresponded with Ibn Sina about the nature of heat and light, in a rather confrontational fashion. Eighteen letters that Ibn Sina sent in answer to his questions survive, covering philosophy, astronomy and physics. His curiosity ran wider than physics. Carried into northern India when a sultan's armies went that way, he wrote a massive book about the country, taking in its religion and philosophy, its caste system and marriage customs, its writing and its numbers.
Ibn Sina was born in 980 in a town near Bukhara and astonished the scholars who met in his father's house. By the age of ten he had memorized the Qur'an and most of the Arabic poetry he had read. He went on to compose nearly 270 treatises and to serve as vizier in Hamadan. Among them is the Canon of Medicine, called the most famous single book in the history of medicine. Europe knew him as Avicenna.
Ibn Rushd held that Aristotle should be our preeminent guide in philosophy, and he commented on nearly the whole Aristotelian corpus. Latin translations began with Michael Scot around 1220, and by the 1230s Christian Europe was calling him simply the Commentator. Some of his positions alarmed church authorities within a generation. Even so, a papal decree of 1341 instructed the arts faculty at Paris to follow the science of Aristotle and his commentator Averroes, with certain exceptions.
Hulegu's forces destroyed the fortress of Alamut, and the scholar inside it was not killed. Hulegu had an interest in science himself and treated al-Tusi with great respect, and al-Tusi became his scientific adviser. Construction of an observatory west of Maragheh began in 1259 and it was operating by 1262, equipped with a four-meter copper wall quadrant, an azimuth quadrant and a fine library. Twelve years of observations went into his Ilkhanic Tables.
Al-Zarqali was hired in Toledo to build instruments for the astronomers working under Qadi ibn Said, and by 1048 he was making them. His patron gave him the books instead of keeping him at the bench. In two years he had mastered mathematics and astronomy, and in 1062 he joined the group as one of its astronomers. Their Toledan Tables, compiled by Muslim and Jewish scholars together, were written in Arabic, and no Arabic copy has survived.
Scholars had argued for centuries about whether the eye sends something out to meet the world or takes something in. Ibn al-Haytham's seven-volume Book of Optics gives the first correct explanation of vision, showing that light is reflected from an object into the eye. He built the argument on experiment rather than abstract theory. His account of the eye's own structure was still wrong, because he had no concept of a lens to work with.
Al-Sufi, a tenth-century Persian astronomer, enlarged and revised Ptolemy's star list into his own Book of the Fixed Stars, finished around 964. Where Greek charts showed Andromeda, Arab observers saw two fish, and al-Sufi drew both. In his notes he recorded a little cloud at the mouth of one fish, al-latkha al-sahabiya, the nebulous smear. It is the earliest known reference to a galaxy other than the Milky Way. He had no way to know what it was, and he wrote it down anyway.
Aldebaran, Algol, Betelgeuse, Rigel, Vega. The names on a modern star chart are mostly Arabic, in slightly Latinized form, and most of them reach us through al-Sufi's star catalog. It carried Ptolemy's stars under their Arabic rather than their original Greek names, along with the ones al-Sufi added himself. A few of our star names are Greek, and the origin of some has never been settled. The Italian astronomer Giuseppe Piazzi drew a great many of the Arabic ones into his 1814 Palermo catalog, which is how they entered modern astronomy.
Before anyone knew about viruses, telling one fever from another was largely guesswork. Al-Razi, serving as chief physician in Baghdad, wrote a treatise called The Book of Smallpox and Measles, and he is credited as the first physician to set smallpox apart from measles. He had no microscope and no theory of infection. He had careful watching, and the nerve to write down what he saw rather than what the authorities said.
Al-Razi kept working files: notes from his reading mixed with observations from his own practice. He never turned them into a book. After he died, around 925, his students assembled the papers and put them into circulation under the title The Comprehensive Book on Medicine, and that is the work later readers knew him by. Over a thousand of his case histories also survive, which is why we know how a medieval physician actually spent his days.
Al-Zahrawi was born in 936 in al-Zahra, a suburb a few miles from Cordoba, and his thirty-volume encyclopedia covered the whole of medicine as he knew it. In the surgical part he ties off bleeding vessels and stitches internal wounds with catgut, a thread the body takes up. Ambroise Pare, the French military surgeon usually credited as the first European to use such sutures, was working five centuries later.
The Hindu word for the sine was jya. Arabic writers kept the sound and wrote jiba, a word that meant nothing in Arabic. In later Arabic writing jiba became jaib, which does mean something: a fold. When European scholars translated those books into Latin, they translated the word in front of them and chose sinus, the Latin for fold. Fibonacci's sinus rectus arcus helped fix it in place, and every sine since has carried it.
We call them Arabic numerals, and the mathematicians of the Islamic world never claimed them. Historians trace the digits back to the Brahmi numerals of India, and they reached Europe not directly from India but through the Arabic world, entering first by way of Spain. Nor did one system simply replace another: in the eleventh century at least three kinds of arithmetic were in use side by side, including finger reckoning written out in words.
Al-Battani observed from ar-Raqqah on the Euphrates, a town made prosperous by the palaces Harun al-Rashid built there, and his tables rest on observations made between 877 and 918. He refined the length of the year to 365 days, 5 hours, 46 minutes and 24 seconds, and he cataloged 489 stars. His measurements of the motion of the sun came out more accurate than the ones Copernicus made six centuries afterward.
Al-Ma'mun continued the patronage of learning his father had started and founded the House of Wisdom in Baghdad, where Greek philosophical and scientific works were translated. He built up a library around it, collecting important works from Byzantium, and set up observatories so astronomers could work from what earlier peoples had recorded. He hired for talent: al-Khwarizmi, al-Kindi, the three Banu Musa brothers, and al-Hajjaj, who first put Euclid's Elements into Arabic.
2A capital 41 kilometers long, mostly still buried
On the tile: Samarra836-892
From 836 to 892 the Abbasid capital was not Baghdad but Samarra, 130 kilometers up the Tigris, and the site is enormous: 41.5 kilometers from north to south, and 4 to 8 kilometers wide. It is the only surviving Islamic capital that keeps its original plan, architecture and arts, and its ninth-century Great Mosque carries a spiral minaret. About 80 percent of the city has never been excavated.
Kairouan, in what is now Tunisia, was founded in 670 and flourished under the Aghlabid dynasty in the ninth century. Part of what kept it going is still there: an open-air reservoir formed by two communicating cisterns, which UNESCO calls one of the most beautiful hydraulic ensembles conceived to provide water to the town. The city was capital of Ifriqiya for five centuries, and stayed the principal holy city of the Maghreb after the political capital moved to Tunis.
The Mosque of the Three Doors in Kairouan was built in 866, and UNESCO describes it as the oldest known Islamic mosque with a sculpted facade, the most ancient existing sculpted facade of Muslim art. It is a modest building in a city famous for something else: the Great Mosque, an architectural masterpiece that was copied across the Maghreb, with a massive square three-story minaret over its courtyard. The record belongs to the small one.
The Great Mosque of Cordoba stands on columns that were already old when the building began: Roman and Visigothic columns reused in Islamic architecture, which UNESCO cites as proof of the monument's authenticity rather than as a shortcut. Cordoba became the seat of an independent caliphate in 929, and between the eighth and the tenth centuries it was the main urban and cultural focus in the western world. In the thirteenth century the mosque became a cathedral.
In the middle of the tenth century the Umayyads built Medina Azahara from scratch as the seat of the Caliphate of Cordoba, a purpose-built capital a few miles from the old one. It prospered for several years. Then the civil war that ended the caliphate in 1009 and 1010 laid it waste, and the place simply left memory: the remains were forgotten for almost a thousand years, until their rediscovery in the early twentieth century.
The story goes that Fatima al-Fihri, whose family had come to Fez from Kairouan, spent her entire inheritance on a mosque for her neighbors, and that her sister Mariam founded a second mosque in the city. It rests on a chronicle written some 450 years afterward, and modern historians doubt that two sisters and two mosques could line up so neatly. The building is not in doubt: al-Qarawiyyin went up between 857 and 859, teaching grew around it, and UNESCO and Guinness World Records call it the oldest university still running.
Cairo was founded in 969 as the headquarters of the Fatimid Caliphate, and parts of its fortification survive in the gates of Bab Zuwayla, Bab al-Nasr and Bab al-Futuh. It was not the first city here. Under the Mamluks the urban fabric spread beyond the walls and took in the earlier capitals of Fustat, founded in 642, al-Askar from 750 and al-Qata'i, laid out around 870, so today's streets run over three older cities.
The mosque of Ahmad ibn Tulun was built between 876 and 879 in al-Qata'i, the city that came before Fatimid Cairo. It has a spiral minaret and symmetrical arches opening onto a vast square court, and it is still standing while al-Qata'i is not. It sits today inside Historic Cairo, among mosques, madrasas, bathhouses and fountains of later centuries, in one of the oldest Islamic cities in the world.
The story goes that the secret of paper was captured at the battle of Talas in 751, when Chinese craftsmen taken prisoner taught their captors the trade. Most scholars now think the technique, which is not very complex, could have moved west out of China before then, though no early non-Chinese paper survives to prove it. Before 712 a ruler at a fortress outside Samarkand was writing on Chinese paper already used on one side. What is documented is a papermaking factory in Baghdad in 796.
Al-Jazari is thought to have served as chief engineer and adviser at the Artuklu Palace, and in 1206 he presented his sultan with the Book of Knowledge of Ingenious Mechanical Devices. It sets out the construction of fifty machines, among them fountains, clocks, automated palace gates, pitchers, locks and bolts, with instructions for building them. Many were fancifully designed as well as useful. Very little else about his life is known.
Musa ibn Shakir was a robber in his youth who turned to science and became highly proficient in astronomy. His three sons were recruited into the House of Wisdom by al-Ma'mun, who had quickly come to appreciate their talents. Jafar Muhammad worked mainly on geometry and astronomy, Ahmad mainly on mechanics, al-Hasan on geometry. Their treatise on measuring figures went into Latin through Gerard of Cremona as the Book of the Three Brothers on geometry.
Eastern Iran has a season of winds that blows for 120 days, and too little water to turn a mill. The first asbads seem to have originated in Sistan in answer to that. An asbad stands two stories tall and turns on a vertical axis, the wind reaching its vanes through openings in the wall. Villages put them in a line along the highest ground, a stretch sometimes a kilometer wide, which ground the grain and also sheltered the houses from storms. The design spread across Islamic lands by the twelfth century.
On the banks of the Tagus outside Toledo stood two great basins that kept the lunar month. When the new moon appeared, water began flowing in through underground pipes. By the seventh day and night the basins were half full; by the full moon they were full. Then, as the moon waned, they lost water at the same rate, and by its twenty-ninth night not a drop remained. Their builder, al-Zarqal, is often confused with the Toledo astronomer of nearly the same name.
Arabic calculators worked on a dust board, writing figures and rubbing them out as the work went along. In Damascus in 952 or 953, al-Uqlidisi wrote a book on Indian arithmetic that showed how to modify the methods for pen and paper instead. The same book is the earliest known text offering a direct treatment of decimal fractions: he saw that a decimal sign was needed and suggested a good one. Historians still argue over how far he took it.
Al-Zahrawi's surgical writing is illustrated, and the pictures have a job to do. His illustrations of surgical instruments were the earliest intended for use in teaching, and for showing how the instruments themselves were made, so a practitioner elsewhere could have them built. He applied cauterization to as many as fifty different operations. His work was highly regarded in the West, particularly after Gerard of Cremona and others translated it.
The standard treatment for a clouded lens was couching, pushing it out of the line of sight with a probe. Ammar ibn Ali al-Mawsili, a scientist from Mosul, is credited instead with the hollow needle, the almuqdah almujawaf, used to draw a soft cataract out of the eye by suction. His Book of Choices in the Treatment of Eye Diseases is unusual in a second way: in it he quotes no other author, Arab or Greek. The manuscript is in the Escorial library in Madrid.
Alcohol comes from al-kohl, elixir from al-iksir, alembic from al-inbiq, and alchemy from al-kimiya, a word that could also mean a way of obtaining something: the way of obtaining happiness, or of touching hearts. Arabic alchemists perfected distillation, and al-Razi described his laboratory so plainly that his terms can still be matched to procedures, taqtir for distilling among them. His equipment list runs from furnace and bellows to the blind alembic and the alembic with an evacuation tube.